Sergei Lavrov and John Kerry said they hoped the plan could avoid military action against Syria.
The UN has confirmed it has received documents from Syria on joining the Chemical Weapons Convention, a key step in the Russian plan.
Syria’s president said it would submit arms data one month after signing.
The US accuses the Syrian government of killing hundreds in a chemical attack in the Ghouta area of the capital, Damascus, on 21 August. The government denies the allegation, blaming rebels.
Russia announced its proposal for dealing with the escalating chemical weapons crisis on Monday, as the US Congress was preparing to vote on whether to back President Barack Obama’s moves towards military strikes.
In a press conference ahead of the Geneva talks, Foreign Minister Lavrov said the resolution of the chemical weapons issue in Syria would make any military strike by the United States unnecessary.
He said there had to be a move away from military confrontation, and that successful talks could lead to a “Geneva 2” meeting.
Secretary of State Kerry said that only the threat of force had spurred Syria to accept relinquishing its chemical weapons, but that he hoped diplomacy could prevent military action.
He said the expectations for the meeting were high – particularly for Russia.
Mr Kerry said: “This is not a game… it has to be real, it has to be comprehensive, it has to be verifiable, it has to be credible, it has to be… implemented in a timely fashion.”
He also rejected President Bashar al-Assad’s suggestion of a 30-day timetable for submitting chemical weapons data.
Mr Kerry added: “President Obama has made clear that should diplomacy fail, force might be necessary.”
Mr Lavrov appeared to admonish Mr Kerry for making a political address. Mr Kerry failed to hear the translation of Mr Lavrov’s final words and asked to hear them again.
Mr Lavrov said in English, “It’s OK John”, only for Mr Kerry to say, smiling: “You want me to take your word for it – it’s a little early for that.”
The BBC’s James Robbins, in Geneva, says these are critical talks, aimed at breaking two and a half years of deadlock over Syria.
Our correspondent says the American and Russian teams are unusually large – packed with weapons experts as well as diplomats.
He says the idea is that detailed talks on the practicalities of chemical disarmament will run in parallel with the hard political graft between Mr Kerry and Mr Lavrov – but it is expected to be a lengthy process, as each side tests the other hard to see if they really can find common ground.
US officials had earlier described Russia’s plan as “doable but difficult”.
Mr Lavrov also gave an outline of the three main phases of the proposal:
- Syria joins the Chemical Weapons Convention, which outlaws the production and use of the weapons
- Syria reveals where its chemical weapons are stored and gives details of its programme
- Experts decide on the specific measures to be taken
Before meeting Mr Lavrov, Mr Kerry held talks with UN-Arab League envoy to Syria, Lakhdar Brahimi.
President Assad earlier appeared on Russian TV to confirm that his country’s chemical weapons would be placed under international control but insisted that “US threats did not influence the decision”.
In his interview, Mr Assad told state-run Rossiya 24 that Syria was sending relevant documents to the UN as part of the process of signing the Chemical Weapons Convention. The UN has confirmed receipt.
Mr Assad said Syria would then submit information on its chemical weapons one month after signing.
He also said that Russia’s proposal was “not unilateral”, adding: “Syria will accept it if America stops military threats and if other countries supplying the rebels with chemical weapons also abide by the agreement.”
The US postponed plans to launch military strikes on Syria after Russia proposed the disarmament.
The main Syrian armed rebel group has already refused to co-operate on the plan.
Gen Salim Idriss of the Free Syrian Army said he categorically rejected it, and insisted that the most important thing was to punish the perpetrators of chemical attacks.
If the talks in Geneva are successful, the US hopes the disarmament process will be agreed in a UN Security Council resolution.
However, Russia regards as unacceptable any resolution backed by military force, or a resolution that blames the Syrian government for chemical attacks.
Moscow has already objected to a draft resolution that would be enforced by Chapter VII of the UN charter, which would in effect sanction the use of force if Syria failed in its obligations.
Russia, supported by China, has blocked three previous draft resolutions condemning the Assad government.
More than 100,000 people have died since the uprising against President Assad began in 2011.